Signal code and program sending system



Aug. 18, 1942. J. w oc 2,293,524

SIGNAL CODE AND PROGRAM SENDING SYSTEM Filed Aug. 21, 1939 Sheets-Sheetl I 59 v 2 6/- 62 0 y p 34- "36 6 f F 22 L V @2 76 I W ZTW.

JOHN H. WHEELOCK 27 0. I AM SIGNAL CODE AND PROGRAM SENDING SYSTEM FiledAug. 21, 1939 5 Sheets-Sheet 2 x 17 0 H i 5e 55 K-z 37 1.3 6

HIE 522% JOHN H. WHEELOCK,

Aug. 18, 19 42.

J. H. WHEELOCK 2,293,524 SIGNAL CODE AND PROGRAM SENDING SYSTEM FiledAug. 21, 1959 5 Sheets-Sheet 3 JOHN H. WHEELOC/L fl/ ZQ $5M Aug. 18,1942. J WHEELQCK 2,293,524

SIGNAL CODE AND PROGRAM SENDING SYSTEM Filed Aug. 21, 1939 5Sheets-Sheet 4 EZ'C UZEW:

JbH/v Z2. WHEEL oc/s Aug. 18, 1942. H. WHEELOCK 2,293,524

SIGNAL CODE AND PROGRAM SENDING SYSTEM 5 Sheets-Sheet 5 Filed Aug. 21,1939 720672269: JBH/v H. WZEELOCK Patented Aug. 18, 1942 UNlTED STATESPATENT @FEICE SIGNAL CODE AND PROGRAM: SENDING SYSTEM John H. Wheelock,Fitzwilliam, N. H., assignor to Signal Engineering & Manufacturing Com=pany, New York, N. Y., a corporation of Massachusetts 8 Claims.

The present invention relates to a signal code and program impulsetransmitting system for controlling the operation of suitable devicesfor sounding or displaying signals at different locations throughout abuilding, or other establishment in which the system is installed.Calling and locating individuals by code number and the transmission ofso-called program signals, to indicate time, or the existence of anemergency, are well known uses of such a dual system.

The object of the invention is to provide a fully automatic signalsystem of the above indicated character, that is adapted to transmiteither a predetermined number of rounds of code sequences, as forlocating individuals, under the control of a code determining device, ora given series of evenly spaced program impulses readily distinguishablefrom any of the code signal sequences, under the control of an auxiliarydevice, such as a time clock, or similar device. According to thepresent invention, the improved system is not only capable ofselectively transmitting code impulses or program impulses, but alsoprovides means for automatically preventing any possible interferencebetween the code and program impulses, as well as for assuringsuccessive transmission of complete sequences of either code or programimpulses, entirely irrespective of whether the code determining deviceis operated before the program control contacts, or vice versa.

By reason of the circuits automatically established in the improvedsystem, any one of the following operations may take place:

(a) Transmission of code sequences for a predetermined number of rounds,in response to operation of a code determining member, such as a key.

(12) Transmission of a predetermined number of program impulses, inresponse to operation of the program controlling contacts, as operatedby a clock, or similar device.

Transmission of a predetermined number of complete rounds of codesequences, in response to actuation of a key, as in (a), automaticallyfollowed by transmission of a predetermined number of program impulses,in response to closure of the program contacts at any time during thetransmission of code sequences.

(d) Transmission of a predetermined number of program impulses, inresponse to functioning of the program contacts, as in (b),automatically followed by transmission of predetermined number ofcomplete rounds of code sequences, in response to actuation of a codedetermining key at any time during the transmission of program impulses.

Summarizing the above noted modes of operation, it is apparent that theentire system works on an automatically non-interfering and successionoperation basis, irrespective of whether a code key or the programdevice operates first, to the end that a complete cycle of codesequences will be followed by a complete round of program impulses, orvice versa. The four modes of operation summarized above, will next bedescribed with reference to the accompanying drawings, in which: a

Fig. 1 is a diagrammatic View, illustrating th system in its normalnon-operating condition.

Fig. 2 illustrates the system of Fig. l, operatic to transmit a codesequence.

Fig. 3 illustrates the system of Fig. 1, operating to transmit programimpulses.

Fig. 4 illustrates the system of Fig. 2, in condition to automaticallyfollow the transmission of code impulses by the transmission of programimpulses.

Fig. 5 illustrates a portion of the system of Fig. 3, in condition toautomatically follow the transmission of program impulses by thetransmission of code impulses.

Fig. 6 is a fragmentary View, illustrating a portion of the parts ofFig. 5 in different positions.

Fig. 7 is a fragmentary view, showing the mechanical relation betweencertain parts of the system.

Figs. 8 to 11 inclusive are fragmentary views illustrating parts of thecode setting device in diiierent positions.

Referring first to Fig. 1, the system includes a code determining deviceof any suitable type, which is shown, for purposes of illustration, ascomprising a key 2;, operable to set up different code combinations,with respect to associated contacts k-l, k-E, k'3, etc. Ihe l:eyactuatedcontacts k-l, k-Z, k-3, etc. are connected to correspondingly designatedcontacts cl c2, etc. of a commutating device C. The contacts cl, 0-2,etc. are in the form of projections spaced around the periphery of aring l, but insulated from each other, and an arm 2 mounted on a shaft 3passing through the ring, is adapted to sue essively. bear on thecontacts c-l, c-2, etc.

A motor M serves to drive the shaft 3 which carries a second arm l,adapted to bear successively on a series of contacts 5 mounted on a ring8 parallel to the ring I, with the contacts 5 formed and arrangedidentically with contacts c-I, c2, etc. and all connected to the ring 6.The arms 2 and 4 are connected together so as to turn in unison with theshaft 3, as shown in Fig. 7, with both arms being insulated from theshaft 3, and being equally flexed to maintain uniform contact pressureas they pass over the projections on the rings I and 3. The ring 6 isconnected by conductor I to one of a pair of spaced master contacts 8,adapted to be bridged by a member 9 mounted on a pivoted arm II]. a

The arm It provides an extension lta bearing on a disk II, also mountedon the shaft 3. The disk I I provides a series of projections I2, havingthe same form as the contacts on ring 6, and the contacts cI, c-2, etc.on ring I, although spanning a smaller angle than the ring contacts,measured in either direction of rotation of the shaft 3. As a result ofthis angular relation between projections I2 and the ring contacts, thecircuit between the master contacts 8 is made and broken by the bridgingmember 9, while the arms 2 and 4 are successively in engagement with thecontacts c-I, c-2, etc. and contacts 5, whereby all arcing is restrictedto the master contacts 8 during operation of the commutating device C.

The motor driven shaft 3 is connected to a control shaft I3 throughreduction gearing I 4, so that the shaft I 3 makes a predeterminednumber of revolutions, three, as shown, for each revolution of the shaft3. The shaft I3 carries a program disk I5, provided around its peripherywith a series of projections I5 that are closer together than are theprojections I2 on the master contactor disk I I, for a purpose whichwill hereinafter appear. An arm I! pivoted at We, bears on the programdisk I5, so that rotation thereof is adapted to impart an oscillatorymovement to the arm IT, to carry a contact I8 rapidly into and out ofengagement with a stationary contact I9. The shaft I3 also carries amotor control cam 29, providing a notch 21 in its periphery, in which isnormally received the free end of an arm 22 pivoted at 22a. An extensionof the arm 22 carries an insulated contact 23, which is maintained outof engagement with a stationary contact 24, as long as the end of thearm 22 remains in the cam notch 2I.

One terminal of the motor M is permanently connected to a suppuy main S,suitably energized from a source of power, not shown, while the othermotor terminal is connected by a conductor 25 to the contact 23 mountedon the arm 22, under control of the cam 20. The stationary contact 24 isconnected by a conductor 26 to a second supply main S, energized fromthe same source as the main S. Therefore, closure of the contacts 23 and24 by the control cam 20, is adapted to establish and maintain anenergizing circuit for the motor M that will be broken once for eachcomplete revolution of the cam 20, or three revolutions of the motorshaft 3.

A starting contact 21 is connected to the conductor 25 between the motorterminal and contact 23, and this contact 21 is adapted to bemomentarily engaged by the key K when the latter is pressed all the wayin, as indicated in dotted lines, to initiate the transmission of codesequences. The key contact k-I is connected by a conductor 28 to astationary contact 29 that is normally engaged by a movable arm 30,forming part of a program relay, generally designated by the referencecharacter P. The relay arm 30 is connected at junction point 3| to theconductor 26 leading to the main S, so that the key contact k-I isnormally energized from the main S, as long as the program relay Premains deenergized. Depression of the key K to engage the startingcontact 2?, as indicated in dotted lines in Fig. 1, thus completes astarting circuit for the motor M, to initiate the transmission of codesequences, as will be hereinafter described.

The program relay P comprises an energizing winding 32 and a mainarmature 33, carrying the arm 38 that is in engagement with contact 29when the winding 32 is deenergized. The armature 33 carries a second arm34 insulated from arm 33, with the arm 34 normally in engagement withstationary contacts 35 and 36, that are under a certain degree offiexure, as indicated. These contacts 35 and 36 are connected byconductors 3'! and 38, in parallel with a pair of normally closedcontacts 39 and 40, with the flexible contact 39 bearing at its end onan extension 4| movable with the arm ll, although insulated therefrom.

One terminal of the winding 32 of the program rela P is connected to thesupply main S, while the other terminal thereof is connected through aresistance 42 to one of a pair of normally open program contacts 43. Aswill be her inafter described, these program contacts 43 are adapted tobe momentarily closed at a predetermined time, under the control of asuitable clockoperated device, not shown, or they can be closedmanually, or by any other means. The other program contact 43 isconnected to the contact 39 which, as previously pointed out, isnormally in engagement with contact 53 that is in turn connected byconductor M to the supply main S.

A pull-in circuit forthe relay winding 32 is provided around theresistance 32 between the junction points t5 and (it, which circuitincludes a pair of relatively movable contacts 47 and 48, one of whichis mounted on the arm 22 cooperating with the motor control cam 23,although insulated therefrom and also from contact 23. With the end ofthe arm 22 in the cam notch 2|, the depressed arm maintains the contactsl! and 43 in engagement, but as soon as the cam 20 starts to turn, thearm 22 rides up on the periphery of the cam to move contact 38 away fromstationary contact 41, while at the same time closing contacts 23 and24.

The program relay P provides a second or auxiliary armature 49 ofconsiderably less weight than the main armature 33, so that the armature49 will pull in when the winding 32 is traversed by a current such aswill flow with the winding in circuit with the resistance 42. Thestrength of the current required to pull in the armature 49, while notsufficient to cause the main armature 33 to pull in, is neverthelesssuificient to hold in the main armature 33, assuming that the latter haspreviously been pulled in by current traversing the shunt circuit aroundthe resistance d2, through contacts 51 and 48. The aux iliary armature59 carries a bridging member 50 insulated therefrom and adapted toengage a pair of spaced stationary contacts 5| when the armature pullsin. Thus contacts 5i are connected in parallel through conductors 52across the normally open program contacts 43, so as to provide means forshort circuiting these contacts whenever the auxiliary armature pullsin.

The contacts 23 and 24 in the holding circuit for the motor M areconnected in parallel through conductors 53 to relatively movablecontacts 54 and 55 that are normally maintained out of engagement by apivoted latch 53, having one end bearing on the contact 55 so as to flexit away from the stationary contact 54. The latch 56 is normally held inthe position shown in Fig. l, by a pivoted armature 51 under control ofthe winding 58 of a latch relay L. One terminal of the winding 58 of thelatch relay is connected to the supply main S, while the other terminalthereof is connected to a stationary contact 59. The contact 59 isnormally out of engagement with a movable contact 69, associated with alatch plate 6| bearing on the bevelled end of the key K when the latteris in non-code determining position, as shown in Fig. 1. When the key Kis depressed and released, upward movement of the plate 6| before itdrops into the key latching notch 62, results in a momentary engagementof contact (iii with contact 59. The latch contact 69 is connected byconductor 63 to a stationary contact 64 normally out of engagement withthe movable arm 36 of the program relay, when the winding 32 isdeenergized. Therefore, momentary engagement between contacts 59 and 6%resulting from operation of the latch plate 6| by depression of a key K,will have no effect on the latch relay winding 53, unless the programrelay P has been previously fully energized to pull in the main armature33.

The particular construction and mounting of the key K and its associatedlatching mechanism, forms no part of the present invention, such alatching mechanism being shown, for example, in Burdick Patent No.1,823,585, issued September 15, 1931, for a Code setting device forsignal sys tems. In order to simplify the showing of the circuits in thesystem of the present invention, the key K, and its latch plate 6|, areshown only diagrammatically in Figs. 1 to 5, inclusive, while the actualconstruction of these parts is illustrated in the several fragmentaryviews showing the parts in different positions.

The program relay P also provides a stationary contact 65, normally outof engagement with the arm 30, with the winding 32 deenergized, thiscontact 65 being connected to the motor circuit conductor 25 at thejunction point as. When the contact 65 is engaged by the arm uponenergization of the program relay P, there is provided a second holdingcircuit for the motor M, as will hereinafter appear from the descriptionof the operation of the system to transmit program impulses.

The system also provides a master relay R, providing a winding Bl havingone terminal thereof connected to the supply main S. The other terminalof winding til is connected from junction point 63 to one master contact8 of the code sending mechanism previously described, so that openingand closing of the contacts 8 will result in operation of the masterrelay R, in accordance with a code sequence, as determined by the ke K.The junction point 68 leading from the master relay winding 61, is alsoconnected to the insulated contact I3 carried by the arm I! bearing onthe program disk [5. The cooperating stationary contact is is connectedby a conductor 69 to one of a pair of spaced stationary contacts Hiadapted to be bridged by the arm 34 of the program relay P, when thewinding 3?. is fully energized. Since the other relay contact it! isconnected directly to the supply main S, opening and closing f thecontacts i8 and i9 by oscillation of the arm ll as the program disk l5rotates, is adapted to successively energize and deenergize the masterrelay winding 61, assuming that the main armature 33 of program relay Phas previously been pulled in.

The master relay R provides relatively movable contacts H, one of whichis connected to the supply main S, while the other is connected to thesupply main S, in circuit with suitable signals i2, such as bells, hornsor lamps. Consequently, successive energizations and deenergizations ofthe master relay winding 61, will cause operation of the signals 72,either in accordance with. a code sequence under the control of the keyK and commutating device C, or in accordance with a series of programimpulses under the control of the program relay P and program disk [5.Having set forth the construction and function of the various devicesentering into the system, the operation thereof will next be described,under the several different conditions previously outlined.

(.4) Transmission of code sequences alone Upon full depression of thekey K, a momentary circuit is established at contact 21, as indicated indotted lines in Fig. 1 and also in Fig. 10. The motor starting currentthen flows through the key K and conductor 28, through the engagedcontact 29 and arm 39 of the program relay P, which is then in adeenergized condition. As soon as the motor starts, turning of the cam20, driven from the motor shaft 3 through the reduction gearing l4,closes contacts 23 and 24, which maintain the motor circuit through theconductors 25 and 26 tothe supply main S during one complete revolutionof the cam 20, which corresponds to three complete revolutions of themotor shaft, as illustrated.

The motor starting circuit through the contact 21, is immediately brokenupon release of the key K, which becomes latched in code determiningposition, as indicated in Figs. 2 and 11, with the end of the key out ofengagement with contact 21. The momentary closure of contacts 59 and 68by the latch plate 6|, which results from depression and release of thekey K, has no effect on the latch relay winding 53, owing to the factthat the contact 64 is out of engagement with the arm 30 of the thendeenergized program relay P.

With the key K in code determining position, as shown in Fig. 2, certainof the key contacts, namely 10-3 and lc4, become energized from thesupply main S through the common contact k-l, the particular selectionof contacts shown being chosen to cause transmission of a code signalsequence corresponding to the numeral twelve. Corresponding contactsc-l, c-3 and c4 of the commutating device C, will also be energized fromthe supply main S, through the connections between the code determiningdevice and these contacts. As the motor shaft 3 rotates, the connectedarms 2 and 4 successively bear upon the contacts c-l, c2, etc. andcontacts 5, so that the ring 6 becomes connected to the supply main S atintervals determined by the arrangement of the then energizedkey-actuated contacts kl, k3 and 7c-4.

Shortly after the arm 2 rides up on the first contact 0-1, the arm Illaalso rides up on the first projection 12 on the disk I I so as to closethe circuit between the master contact members 8. When this occurs, thecircuit through the wind ing 6'! of the master relay R is completed,thereby energizing the signals 12 to transmit the first impulse of thecode sequence. Since the projections I2 on the disk II have a smallerangular span than the ring contacts, the circuit of the winding 61 isbroken at the master contacts 8, before the arms 2 and 4 leave theircontacts; as a result, no arcing can take place at the ring contacts.

Continued rotation of the arm 2 to engage contacts c2, c3 and c4, willresult in the transmission of a second and a third signal impulse, witha pause between the first and second impulses, due to the non-energizedcontact c2, to correspond to the signal sequence twelve. This signalsequence will be repeated as the shaft 3 makes a second and thirdrevolution, assuming that the ratio of the gearing l4 between the shafts3 and I3 is three to one. As the shaft 3 completes its third revolution,the arm 22 enters the notch 2| on the periphery of the control cam 20,thereby separating contact 23 from'contact 24, to break the motorcircuit. The parts of the system thereupon come to rest in the positionof Fig. 1, even though the key K remains in its latched position. Theparticular latching arrangement for the key K is shown merely forillustrative purposes, since the invention contemplates the use of anydesired type of code determining device providing means for setting updifferent contact combinations in cooperation with the commutatingdevice C.

During the transmission of signal impulses in accordance with theselected code sequence, as described above, the rotation of the programdisk I 5, causes the contacts I8 and I9 to be successively closed andopened as the arm I! bears on the projections [6. Such operation of thecontacts l8 and I9, however, has no effect on the master relay winding61, since the contact l9 connected to the program relay contact 10 isdisconnected from the supply main S", while the program relay P remainsdeenergized. Therefore, the system continually remains in a conditionwherein closure of the program contacts 43 will cause transmission ofprogram impulses, as will next be described.

(B) Transmission of program impulses alone Let it now be assumed thatwith the system in the non-operating condition of Fig. 1, programcontacts 43 are momentarily closed, as by means of a suitableclock-operated device, not shown. When this occurs, a circuit isestablished for the program relay winding 32 from the supply main Sthrough conductor 44, then closed contacts 40 and 39, to the junctionpoint 46. From this oint, the circuit is through the closed contacts 41and 48 to junction 45 and the lower terminal of the winding 32, therebyshunting out the resistance 42 and causing sufficient energization ofthe winding 32, as to pull in both the armatures 33 and 49. As theauxiliary armature 4&9 pulls in, bridging member 50 engages contactsthereby establishing a holding circuit around the program contacts 43.so that the subsequent opening of these contacts has no effect on thecontinued energization of winding 32.

Pulling in of the main armature 33, as shown in Fig. causes the relayarm 30 to disengage contact 29. thereby entirely disconnecting key K ofthe code determining device from the supply main S. This is followed byengagement of arm 30 with the stationary contact 65, to establish acircuit for the motor M from the junction point 66 of motor conductor 25to main S. Turning of the control cam 2|! by the motor shaft 3,thereupon causes the arm 22 to ride out of the cam notch 2|, so as todisengage contacts 41 and 43 while engaging contacts 23 and 24, toestablish a parallel holding circuit for the motor, the purpose of whichwill hereinafter appear. Upon separation of the contacts 47 and 48, theshunt circuit around the resistance 42 is broken, thereby reducing thecurrent flowing through the program relay Winding 32, but not sumcientlyto permit the main armature 33 to drop back.

Pulling in of the main armature 33 also causes the arm 34 to leavecontacts 35 and 36 and engage the contacts l3, thereby establishing acircuit from the supply main S to the stationary contact is.Subsequently, rotation of the program disk 55 from, the position of Fig.1 to the position of Fig. 3, turns the arm H as it engages a projectionit, to engage the contact l8 with the contact l 9. When this occurs, acircuit is established for the master relay winding 61 from the junctionpoint 68, thereby transmitting the first impulse of the program signalsequence. As previously pointed out, the program disk projections it areclosely spaced, so that continued rotation of the disk l5 causes aseries of evenly spaced signal impulses to be given in rapid successionand without code significance. The number of program signal impulseswill depend upon the number of projections E5 on the disk l5, and asshown, the impulses are continued over a period greater than thatrequired for sounding one round of code impulses.

As the program disk l5 nears the completion of one revolution from theposition of Fig. l, the arm ll drops into a notch l5a on the peripheryof the disk, thereby opening the circuit of the program relay winding 32as the contacts 39 and 3 separate, as indicated in dotted lines in Fig.4. When this occurs, both armatures 33 and 69 fall back, therebyinterrupting the motor circuit at the contact 65 and opening thepreviously bridged contacts El in parallel with the then open programcontacts 43. The motor. however, continues to operate, due to the factthat the motor-holding circuit beyond the junction point 65 in conductor25, is still closed through contacts 23 and 25. Consequently, the disk[5 turns through a few more degrees to bring it to the position of Fig.l, whereupon the motor stops as the arm 22 enters the notch 2| to causeseparation of contacts 23 and 24. The resulting reengagement betweencontacts 39 and 49 has no effect on the program relay winding 32, sinceboth pairs of contacts 43 and 5| are then open, and there is no way inwhich current can flow to the winding 32. All parts of the system aretherefore restored to the condition of Fig. l at the completion of thetransmission of the series of program impulses by the signals 12.

Having described the operation of the system to cause the transmissionof code sequences alone, as well as the transmission of a series ofprogram impulses alone, there will next be described the operation ofthe system, wherein the transmission of code sequences in response toinitial actuation of a key, is automatically followed by transmission ofprogram impulses, in

response to closure of the program contacts at any time during thetransmission of code sequences.

(C) Transmission of code impulses followed by program impulses Let itnow be assumed that during the transmission of code signal sequences inresponse to operation of a key K, as previously described with referenceto Fig. 2, the program contacts 43 are closed momentarily. When thisoccurs, current from the supply main S, is unable to flow to the programrelay winding 32, through the shunt circuit around the resistance 42,owing to the fact that the contacts 41 and 4B are then held separated bythe arm 22 riding on the periphery of the motor control cam 25).Therefore, the current traversing the winding 32 is so limited by theresistance 42, that only the auxiliary armature 49 pulls in to close thecontacts and establish a holding circuit for the partially energizedwinding 32, around the program contacts 43, when the latter are opened.Since only the auxiliary armature 49 has pulled in, as shown in Fig. 4,the program relay arm 30 remains down to maintain the connection of thecode sending mechanism to the supply main S through the contact 29.Since the other program relay arm 34 also remains down, the contacts l3and I9 under the control of the program disk i5, remain disconnectedfrom the supply main S, so that transmission of the code impulsesremains undisturbed, in spite of the closure of program contacts 43 andpulling in of the auxiliary armature 49. It is also to be noted thatwhile the program relay arm 34 remains down, a shunt circuit ismaintained around the then closed contacts 39 and 43, by reason ofengagement of the arm 34 with stationary contacts 35 and 36.

As the program disk l5 near the completion of one revolution,coincidentally with transmission of the code sequences, the arm I! dropsinto the notch I5a so as to cause separation of the contacts 39 and 45.The opening of these contacts, however, does not permit the auxiliaryarmature 49 to drop, since the circuit to the program relay winding 32through the resistance 42 is then maintained through the conductors 37and 38 and the contacts 35 and 36, then bridged by the arm 34.

Consequently, when the motor M comes to rest at the end of thetransmission of three complete rounds of code sequences, reclosure ofcontacts 47 and 48 as the arm 22 enters the notch 2!, reestablishes theshunt circuit around the re sistance 42 to cause full energization ofthe program relay Winding 32. The resulting pull up of main armature 33thereupon restarts the motor M as contact 65 is engaged by relay arm 30that is always connected to the supply main S, whereupon there followsthe transmission of a complete series of program impulses, as previouslydescribed with reference to Fig. 3. In other words, closure of theprogram contacts 43 at any time during the transmission of codesequences, results in placing the system in condition to automaticallyproceed with the transmission of a complete series of program impulsesas soon as the motor comes to rest at the completion of the last roundof code sequences. It is to be noted that as the program relay arms 38and 34 pull up, the initially flexed contacts 35 and 36 follow the arm35, until after the arm 38 engages motor starting contact 65, and theprogram disk [5 has moved arm I! out of the notch 15a to close contacts39 and 4% That is to say, the following contacts 35 and 36 are notdisengaged from the upwardly moving relay arm 34 until after the motor Mhas been restarted to initiate a complete series of program impulses.

As previously pointed out, the system also contemplates the provision ofmeans whereby the transmission of program impulses in response toclosure of the program contacts 43, is automatically followed bytransmission of three complete rounds of code sequences in response toactuation of a code determining key at any time during the transmissionof program impulses, and there will next be described the operation ofthe system on this basis.

(D) Transm ssion of program impulses followed by code impulses Shouldthe switchboard operator receive an incoming call during thetransmission of pro gram impulses, as described with reference to Fig.3, and desire to broadcast through the sys= tem a given code number forthe person wanted,- the operator immediately pushes in the selected codekey K, without waiting for the transmission of the program impulses tobe completed.

When the key K is pressed all the way in, as shown in dotted lines inFig. 1, engagement of the motor starting contact 2'! by the end of thekey, has no effect on the motor M, since at that time the stationarycontact 2% of program relay P is disconnected from the supply main S, byreason of the main armature 33 being held up during the transmission ofprogram impulses, see Fig. 3. However, as the key K is pressed in andreleased, the contact 63 is momentarily engaged with the contact 59 asthe latch plate BI is moved upwardly to its extreme position, beforedropping into the notch 62 to latch the key in code determiningposition. Since the stationary contact 64 of the program relay is atthat moment connected to the supply lmain S through the then raisedrelay arm 39, engagement between contacts 59 and 69 serves to energizethe winding 58 of the latch relay L, as shown in Figs. 5 and 9.

Energization of winding 58 pulls in the armature 51, thereby permittingthe pivoted latch 56 to turn in a counterclockwise direction, asindicated, to cause engagement between contacts 54 and 5-5, and therebyprovide a shunt circuit in parallel with the then closed motor-holdingcontacts 23 and 24. In other words, closure of contacts 54 and 55 placesthe system in condition for restarting the motor M, although at thatmoment, actuation of the code determining key K has no efiect, due tothe disconnection of the contact 29 from the supply main '5, during thetransmission of program impulses.

Continued rotation of the program disk [5, following the depression andlatching-in of a key K, as described above, carries on transmission ofthe program impulses until near the completion of one revolution of thedisk l5, whereupon the arm I? drops into the notch 15a to separatecontacts 39 and 48. While the resulting deenergization of the programrelay winding 32 permits the main armature 33 to drop, con-. nection ofthe contact 29 to the supply main S has no immediate eirect, since atthat moment, the arm 2 is bearing on the periphery of the ring I and istherefore insulated from the energized commutating contacts c-l, c2,etc.

As previously pointed out, the angular relation between the notches |5aand 2| is such that the arm 22 enters the notch 2| very shortly afteropening of the contacts i8 and H) has deenergized the program relaywinding 32 at the completion of the transmission of a complete series ofprogram impulses. When this occurs, the previously closed holdingcircuit .for the motor M is broken at the contacts 23 and 24, but themotor does not stop, owing to the previous closure of contacts 54 and toprovide a shunt circuit around the contacts 23 and 24. Therefore, thecontinued operation of the motor M results in the immediate transmissionof code sequences, as determined by the circuits established through thedepressed key K. Obviously, the motor M will continue to operate throughthree complete revolutions of the shaft 3, due to reclosure of thecontacts 23 and 2 1.

After the motor M has turned the cam 26 sufficiently to reengage theholding contacts 23 and 24, a pin 73 on the disk l5, engages the pivotedlatch 56. It is evident from a consideration of Fig. 5, that when thelatch 56 turns into position to permit closure of contacts 54 and 55, abeveled surface 56a on the latch will be disposed in the path of the pinit. Therefore, continued rotation of the disk l5, through a few degrees,following the automatic initiation of code sequences, as describedabove, will result in turning the latch back to the position of Fig. l,to separate the contacts 54 and 55, as shown in Fig. 6. Therefore, thesystem is restored to the condition of Fig. 1, upon the completion ofthe transmission of code sequences, and when the motor M comes to rest,with the arm 22 in the notch 21 of the motor-controlled cam.

From the foregoing, it is apparent that the system of the presentinvention works on an of said device, means for transmitting a series ofimpulses with a different significance under the control of an auxiliarycontact making device, a common driving means for said impulsetransmitting means and connections between said impulse transmittingmeans for controlling the operation of said driving means and causingthe transmission of one or more complete rounds of code impulses inresponse to initial operation of said code determining element, whilepreventing transmission of series impulses in response to operation ofsaid auxiliary contact making device during the transmission of codeimpulses, with said connections between said transmitting means alsoserving to automatically cause continued operation of said driving meansand the transmission of said series impulses upon the completion of thelast round of code impulses.

2. A signal sending system, comprising in combination, a codedetermining device, means for transmitting code impulses under thecontrol of a manually operable code determining element of said device,means for transmitting a series of impulses with a differentsignificance under the control of an auxiliary contact making device, acommon driving means for said impulse transmitting means and connectionsbetween said impulse transmitting means for controlling the operation ofsaid driving means and causing the transmission of -a series of impulsesin response to operation of said auxiliary device, while proventingtransmission of code impulses in response to actuation of saiddetermining element at any time during the transmission of said seriesimpulses, with said connections between the impulse transmitting meansalso serving to automatically cause continued operation of said drivingmeans and the transmission of code impulses immediately following thecompletion of the transmission of said series impulses.

3. In a signal sending system, the combination with a code determiningdevice, a device for transmitting impulses according to a selected codeof said determining device, a device for transmitting a series ofimpulses with a significance different from that of the selected code,and a common driving means for both of said impulse transmittingdevices, of means for independently initiating operation of said drivingmeans for transmission of either type of impulse over a predeterminedperiod, and means for sustaining operation of said driving means whilecausing either type of impulse to automatically follow the other,irrespective of which type of impulse is intially transmitted.

4. In a signal sending system, the combination with a code determiningdevice, a device for transmitting impulses according to a selected codeof said determining device, a device for transmitting a series ofimpulses with a significance different from that of the selected code.and a common driving means for both of said impulse transmittingdevices, of means for independently initiating operation of said drivingmeans for transmission of either type of impulse over a predeterminedperiod, and means for automatically preventing interference betweentransmission of the two types of impulses, irrespective of continuedoperation of said driving means and which type of impulse is initiallytransmitted.

5. In a signal sending system, the combination with a code determiningdevice, a device for transmitting impulses according to a selected codeof said determining device, a device for transmitting a series ofimpulses with a significance different from that of the selected code,and a common driving means for both of said impulse transmittingdevices, of means for initiating operation of said driving means forcausing transmission of code impulses over a predeter mined period inresponse to initial actuation of said code determining device,automatically followed by transmission of said series impulses inresponse to subsequent actuation of the series impulse transmittingdevice, at any time during the transmission of code impulses.

6. In a signal sending system, the combination with a code determiningdevice, a device for transmitting impulses according to a selected codeof said determining device, a device for transmitting a series ofimpulses with a significance different from that of the selected code,and a common driving means for both of said impulse transmittingdevices, of means for initiating operation of said driving means forcausing transmission of series impulses, over a predetermined periodautomatically followed by transmission of code impulses in response tosubsequent actuation of the code determining device, at any time duringthe transmission of said series impulses.

7. In a signal sending system, the combination with a code determiningdevice, a device for tranmitting impulses according to a selected codeof said determining device, a device for transmitting a series ofimpulses with a significance different from that of the selected code,and a common driving means for both of said impulse transmittingdevices, of means for initiating operation of said driving member forcausing transmission of code impulses over a predetermined period inresponse to actuation of said code determining device, means fortemporarily withholding transmission of said series impulses in responseto actuation of said series transmitting device, at any time during thetransmission of code impulses, and means for sustaining operation ofsaid driving means to cause transmission of series impulses immediatelyfollowing completion of the transmission of code impulses.

8. In a signal sending system, the combination with a code determiningdevice, a device for transmitting impulses according to a selected codeof said determining device, a device for transmitting a series ofimpulses with a significance different from that of the selected code,and a common driving means for both of said impulse transmittingdevices, of means for initiating operation of said driving means fortransmitting a series of impulses over a predetermined period inresponse to actuation of said series transmitting device, means fortemporarily withholding transmission of code impulses in response toactuation of said determining member at any time during transmission ofsaid series impulses, and means for sustaining operation of said drivingmeans to cause transmission of code impulses immediately following thecompletion of the transmission of series impulses.

JOHN H. WHEELOCK.

